DFT related softwares: VASP,ab initio,DFTB,ELK,WIEN2K

There are many DFT(density functional theory) related softwares,for example,VASP,ab initio,DFTB,ELK,WIEN2K,and so on. Which one do you use?
What are the advantages and disadvantages of these first principle softwares in your opinion?